package com.sbl.bajw.common;

public class CoordConver {
    //
    // Krasovsky 1940
    //
    // a = 6378245.0, 1/f = 298.3
    // b = a * (1 - f)
    // ee = (a^2 - b^2) / a^2;
    static double a = 6378245.0;
    static double ee = 0.00669342162296594323;
    
    static double pi = Math.PI;

    //
    // World Geodetic System ==> Mars Geodetic System
    public static double[] converWgs84ToGcj02(double wgLon,double wgLat)
    {
    	double mgLat;
    	double mgLon;
        
    	if (outOfChina(wgLat, wgLon))
        {
            mgLat = wgLat;
            mgLon = wgLon;
            return new double[]{wgLon,wgLat};
        }
        double dLat = transformLat(wgLon - 105.0, wgLat - 35.0);
        double dLon = transformLon(wgLon - 105.0, wgLat - 35.0);
        double radLat = wgLat / 180.0 * pi;
        double magic = Math.sin(radLat);
        magic = 1 - ee * magic * magic;
        double sqrtMagic = Math.sqrt(magic);
        dLat = (dLat * 180.0) / ((a * (1 - ee)) / (magic * sqrtMagic) * pi);
        dLon = (dLon * 180.0) / (a / sqrtMagic * Math.cos(radLat) * pi);
        mgLat = wgLat + dLat;
        mgLon = wgLon + dLon;
        
        return new double[]{mgLon,mgLat};
    }

    static boolean outOfChina(double lat, double lon)
    {
        if (lon < 72.004 || lon > 137.8347)
            return true;
        if (lat < 0.8293 || lat > 55.8271)
            return true;
        return false;
    }

    static double transformLat(double x, double y)
    {
        double ret = -100.0 + 2.0 * x + 3.0 * y + 0.2 * y * y + 0.1 * x * y + 0.2 * Math.sqrt(Math.abs(x));
        ret += (20.0 * Math.sin(6.0 * x * pi) + 20.0 * Math.sin(2.0 * x * pi)) * 2.0 / 3.0;
        ret += (20.0 * Math.sin(y * pi) + 40.0 * Math.sin(y / 3.0 * pi)) * 2.0 / 3.0;
        ret += (160.0 * Math.sin(y / 12.0 * pi) + 320 * Math.sin(y * pi / 30.0)) * 2.0 / 3.0;
        return ret;
    }

    static double transformLon(double x, double y)
    {
        double ret = 300.0 + x + 2.0 * y + 0.1 * x * x + 0.1 * x * y + 0.1 * Math.sqrt(Math.abs(x));
        ret += (20.0 * Math.sin(6.0 * x * pi) + 20.0 * Math.sin(2.0 * x * pi)) * 2.0 / 3.0;
        ret += (20.0 * Math.sin(x * pi) + 40.0 * Math.sin(x / 3.0 * pi)) * 2.0 / 3.0;
        ret += (150.0 * Math.sin(x / 12.0 * pi) + 300.0 * Math.sin(x / 30.0 * pi)) * 2.0 / 3.0;
        return ret;
    }
    
    public static double[] converGcj02ToDb09(double gg_lon,double gg_lat)
    {
    	double x_pi = 3.14159265358979324 * 3000.0 / 180.0;  
    	
	    double x = gg_lon, y = gg_lat;  
	    double z = Math.sqrt(x * x + y * y) + 0.00002 * Math.sin(y * x_pi);  
	    double theta = Math.atan2(y, x) + 0.000003 * Math.cos(x * x_pi);  
	    double bd_lon = z * Math.cos(theta) + 0.0065;  
	    double bd_lat = z * Math.sin(theta) + 0.006;  
	    double[] results = new double[2];
	    
	    results[0] = bd_lon;
	    results[1] = bd_lat;
	    return results;
    }
	
    public static double[] converWgs84ToDb09(Double lon,Double lat)
    {
    	if(lon == null || lat == null){
    		return new double[]{0,0};
    	}
    	double[] GCJ02Coords = converWgs84ToGcj02(lon, lat);
    	double[] Db09Coords = converGcj02ToDb09(GCJ02Coords[0],GCJ02Coords[1]);
    	return Db09Coords;
    }
}